Analytical Calculation on the Load - Displacement Curve of Grouted Soil Anchors

Abstract

The load-displacement curve of anchors can be used as a basis for quality tests, and it is also important in the stability analysis of the combined supporting structure of anchors. Most of the existing analytical methods can only solve the partial pullout process of grouted soil anchors and obtain local load-displacement curves. To obtain a complete loaddisplacement curve, mechanical differential equations for the anchoring section in each stage were derived in this study based on a softening shear model of the anchor-soil interface and a load transfer model of the anchoring section. Combined with boundary conditions, the displacement, axial force, and shear stress distributions along the anchoring section and the analytical solutions for the load-displacement curve in the entire pullout process of anchors were obtained. The accuracy of the proposed method was verified by a pullout test on a foundation pit in Chongqing, China. Results show that a complete load-displacement curve is obtained with the proposed analytical method and a theoretical curve is consistent with a field pullout curve. The shear stress on the anchoring section is irregularly and non-uniformly distributed with a single peak. The load-displacement curve is influenced by the changes in parameters, such as anchorage length, anchorage radius, elastic modulus of the anchoring section, and residual shear coefficient. The present study accurately simulates the entire pullout process of anchors, determines their ultimate bearing capacity, obtains a complete load-displacement curve, and provides a theoretical basis for the quality evaluation and modelling analysis on grouted soil anchors.